Field of the Invention
This invention relates to a package, a cap and a module for optoelectronic semiconductor devices which are required to operate at a high speed in optoelectronic communication systems. In particular, this invention relates to an airtight package and a cap for semiconductor devices containing optoelectronic devices and peripheral ICs. The term "optoelectronic devices" is used herein to refer to a device which converts electric signals to light signals or vice versa. Examples of optoelectronic devices are a laser diode (LD), a light emitting diode (LED), and a photodiode (PD). The term "peripheral IC" is used to refer to a device which somehow processes electrical signals associated with an LD or an LED or electrical signals from a PD. Examples include an amplifier, a comparator, a multiplexer and a demultiplexer. Small-sized packages are excluded from the scope of the present invention. Low-speed operating semiconductor devices are also excluded from the consideration of the invention. The object of the invention is an improvement of a large-sized package for installing high-speed operating semiconductor devices.
This invention is particularly applicable to such large packages and caps having at least a side of a length Q which satisfies an inequality Q.gtoreq.c /(2v .epsilon..sup.1/2), where c is the velocity of light (3.times.10.sup.11 mm/s) in vacuum, v is the maximum frequency (Hz) at which the device operates, and .epsilon. is the dielectric constant of the circuit plate of the semiconductor device stored in the package. The purpose of the invention is to suppress parasitic oscillation, cross-talking, and noise caused by uncontrollable interactions among devices in such a large package.
This application claims the priority of Japanese Patent Application No.9-207148 (207148/97) filed Jul. 15, 1997 which is incorporated herein by reference.